R-448A / Solstice N40 (commercial, zeotropic)

R-448A PT Chart

The full R-448A pressure-temperature reference table, from -30 to 130°F, with both the bubble and dew columns its 7.1 to 10.9°F glide requires. Use the dew point for superheat and the bubble point for subcooling. Checked cell by cell against 3 other published tables, 1 of them a separate publisher: Arkema, Honeywell and CoolProp. One of them, Arkema, has a full column on file here, so this chart prints where that table and ours disagree at every pressure instead of quietly picking one. The widest gap on the bubble column, which is the one compared here, is 0.19 degrees F, against Arkema, at 118 psig.

Field brief

211 psigbubble point 90°F (subcooling), dew point 99.1°F (superheat). At 89 psig, bubble 40°F and dew 50°F.bubble / dew

GlideAbout 7.1 to 10.9°F, wide. Reading the wrong column is a large error on a commercial rack; dew for superheat, bubble for subcooling.7.1 to 10.9°F

UseR-404A and R-22 replacement for supermarket and commercial refrigeration racks.commercial

Where you left off

Saved in this browser, which can get cleared. to keep them permanently and work with no signal.

Read the R-448A chart at your gauge pressure

The chart below is the reference. This reads it at the pressure you actually have, off the bubble or dew column the line you are measuring calls for, and works out superheat or subcooling once you add the line temperature.

Refrigerant

Which line is the reading from

the big insulated line, for superheat

What you have

Gauge pressure

Line temperature optional, for superheat

Saturation temperature dew point, the column superheat uses40.1°F

The other column bubble point, which subcooling uses30.0°F

A blend has two saturation temperatures at one pressure. On the suction line the dew point is the one to use. Reading the bubble point instead would put the saturation temperature 10.1°F lower, which makes the superheat come out 10.1°F higher than it is.

72.3 psig is a published row of the R-448A (Solstice N40) chart, not an interpolated value. Glide at this pressure is 10.1°F.

Add the suction line temperature to get superheat from this reading.

Where this number comes fromIntry Verified

Calculated from

R-448A (Solstice N40) PT chart, dew column. Table looked up from a named datasheet; rack statements quoted from publisher documents, cited beside the sentence. See the full receipt ↓

Run with

Pressure72.3 psig, suction line
Saturation40.1°F, dew point
Chart rowa published row of the chart

Checked

Every figure an Intry calculator computes comes from a locked source module, not hand-typed. 28790 automated checks re-derive and source-check the numbers against the locked modules each figure is traced to: the manufacturer PT tables behind the saturation temperatures, superheat and subcooling, and the transcribed code and service-literature constants behind the charge, metering, airflow, approach and discharge line figures, each quoted with its own source in the panel it appears in before each deploy. This is our own deterministic gate, not a third-party audit.

Final say

The unit nameplate and the manufacturer's charging chart have final say.

What Intry Verified means

Intry Verified · Build CAA0BB9 · 2026-09-11

R-448A Pressure-Temperature Table

R-448A saturation temperatures at gauge pressure (psig): bubble (subcooling) and dew (superheat).
R-448A
Pressure (psig)	Bubble °F (subcooling)	Dew °F (superheat)	Publisher spread (°F)
10.4	-30°F	-19.1°F	0
13.5	-25°F	-14.3°F	0
17	-20°F	-9.2°F	0
20.8	-15°F	-4.3°F	0
24.9	-10°F	0.7°F	0
29.3	-5°F	5.5°F	0.11
34.2	0°F	10.6°F	0
39.4	5°F	15.4°F	0
45.1	10°F	20.4°F	0
51.2	15°F	25.4°F	0
57.8	20°F	30.4°F	0
64.8	25°F	35.3°F	0
72.3	30°F	40.1°F	0
80.4	35°F	45.1°F	0
89	40°F	50°F	0
98.2	45°F	54.9°F	0
108	50°F	60°F	0
118	55°F	64.5°F	0.19
129	60°F	69.5°F	0.18
141	65°F	74.6°F	0.04
154	70°F	79.6°F	0.19
167	75°F	84.3°F	0.14
181	80°F	89.3°F	0.17
195	85°F	94°F	0.03
211	90°F	99.1°F	0.15
227	95°F	103.8°F	0.09
244	100°F	108.6°F	0.08
262	105°F	113.4°F	0.08
281	110°F	118.3°F	0.13
300	115°F	122.9°F	0.05
321	120°F	127.7°F	0.02
343	125°F	132.5°F	0.09
365	130°F	137.1°F	0.07

About the spread column. It is the widest gap in saturation temperature between the published tables we hold, at that pressure, on the bubble column. Across this chart the widest is 0.19°F, at 118 psig. Our table and 1 other published table are compared here: 1 is a separate publisher. A narrow spread means the charts agree, which is not the same as the charts being right: they are all computed from equations of state fitted to lab data, and no field measurement settles it.

Where this table comes from. Hudson Technologies R-448A liquid and vapor chart, Solstice N40.

Checked against Arkema Forane, all 33 shipped bubble cells within 0.5 psig, and all 33 dew points within 0.2 F [separate publisher]
Checked against Honeywell Solstice N40, agrees [same model]
Checked against CoolProp reference data, agrees [same model]

A separate publisher can catch a transcription, edition or rounding error. A cross-check marked same model resolves to the same equation of state as the base table, so it is a consistency check rather than independent confirmation. One marked same printing prints numbers identical to another table listed here, so the two are one witness and we do not count them twice. Sources last re-verified 2026-08-25.

Read the low-side (suction) pressure and its dew temperature for superheat, and the high-side (liquid) pressure and its bubble temperature for subcooling. The chart is in psig (gauge) and °F. To convert: kPa gauge = psig × 6.895; °C = (°F − 32) / 1.8. The table opens in psig and °F; the buttons above it show the same rows in bar or kPa (gauge) and °C.

R-448A PT Chart FAQs

What is the R-448A pressure at a 40F bubble point?

On the R-448A PT chart, a 40F bubble point corresponds to about 89 psig, where the dew point is 50F. At 211 psig the bubble point is 90F and the dew point is 99.1F. R-448A (Honeywell Solstice N40) is a zeotropic R-404A and R-22 replacement for commercial refrigeration, with a wide 7.1 to 10.9F glide.

Why does the R-448A PT chart have two temperature columns?

R-448A is a zeotropic blend, so at any given pressure it boils and condenses across a range of temperatures rather than at one point. The lower temperature is the bubble point and the higher one is the dew point; the gap is the glide, about 7.1 to 10.9 degrees F for R-448A, wider than most comfort-cooling refrigerants. The chart lists both columns so you read the correct one for each measurement.

Do I use bubble or dew point for R-448A superheat and subcooling?

Use the dew point for superheat and the bubble point for subcooling. Superheat is measured on the suction line where the refrigerant is fully vapor, which is the dew side. Subcooling is measured on the liquid line where it is fully liquid, which is the bubble side. Because R-448A glides 7.1 to 10.9 degrees F, using the wrong column introduces a large error, enough to misdiagnose a commercial rack charge.

What units is this R-448A PT chart in, and how do I convert to kPa or Celsius?

The table is in psig (gauge pressure) and degrees Fahrenheit, the field-standard units in North America. To convert pressure to kPa (gauge), multiply psig by 6.895. To convert temperature to Celsius, use C = (F - 32) / 1.8. The table opens in psig and degrees Fahrenheit; the buttons above it show the same rows in bar or kPa (gauge) and degrees Celsius.

Related HVAC Tools

Superheat & Subcooling Calculator

Enter your R-448A readings; the calculator splits bubble and dew for you and returns the verdict.

R-449A PT Chart

The Opteon XP40 alternative commercial blend, with its own bubble and dew columns.

R-404A PT Chart

The refrigerant R-448A replaces, read on a single saturation column.

01Source
receipt

Where these numbers come from

The R-448A pressure-temperature table on this page is looked up from a named datasheet, not computed here, and the charge check under it reads that table. The charge check's method, bands, airflow precondition and hazards come from the charging documents listed after the datasheet, the same documents the superheat calculator's receipt names. The charge check under the table can also print commercial-rack statements for R-448A: the station the suction line temperature was taken at, with what the publishers state there, receiver charging on a receiver system and the R-404A changeover. Those statements are quoted from the 8 publisher documents listed after the charging documents; a quoted sentence is cited beside itself with the publisher, the document as the publisher identifies it, and the page where the sentence is quoted.

R-448A pressure-temperature table: Hudson Technologies R-448A liquid and vapor chart, Solstice N40. Its cross-checks, and which of them are separate publishers, are marked under the table above.
CEC-400-2022-010-AP, Reference Appendix RA3 Table RA3.2-1 (Installer Testing at Final): The pass and fail bands, and the conditions they hold under. Variable metering devices are judged on subcooling to plus or minus 3 degrees F of the manufacturer-specified target; fixed orifices on superheat to plus or minus 5 degrees F of the target for the conditions; the metering device itself against the manufacturer's specification or 4 to 25 degrees F. The same table states the envelope those tolerances hold inside, and the engine checks it before applying any of them: outdoor dry-bulb 55 to 115 degrees F on a fixed orifice and 55 to 120 on a variable metering device, with return-air dry-bulb at or above 70. The Installer row is the one shipped, never the looser ECC and HERS Rater row beside it.
CEC-400-2022-010-AP, Reference Appendix RA3 Table RA3.2-2 (target superheat): The target superheat grid for fixed-orifice charging, indexed by indoor wet-bulb and outdoor dry-bulb. Cells are machine-parsed from the appendix rather than transcribed by hand, and a sample was compared against a manufacturer grid from a different publisher as an outside check. The comparison is disclosed rather than claimed as proof: two publishers printing the same targets can inherit one lineage.
CEC-400-2022-010-AP, Joint Appendix JA6.1.6.3 (the airflow precondition): Why this tool checks airflow before it grades a charge, and why it will refuse to grade one. Items 1 to 3 each require that the minimum airflow requirement from item 4 is satisfied before their charge criteria are valid, so a superheat or subcooling reading taken on restricted airflow is not a charge measurement. The direction depends on the metering device: on a fixed orifice a starved evaporator drives superheat DOWN and widens the temperature split, which reads like an overcharge, while on a TXV the valve holds superheat and the fault shows in suction pressure and subcooling. That is the confound the whole air-side check exists to separate.
Carrier PH5SAN5, Carrier SM10-R454B-03, Carrier 25SCA5, Goodman IOG-4048C, ICP 428 01 5106 00, Trane 88-M5MHWUN-1A-EN, Rheem RD16AY, and Bosch service literature: Which charging method a given machine actually permits, and when the manufacturer says not to check the charge at all. Carrier PH5SAN5 (R-454B installation instructions) states the outdoor window it publishes for checking charge and states the airflow precondition directly; Trane and Bosch reach the same place in their own words. Carrier SM10-R454B-03 supplies the sentence defining what a dashed cell on a superheat grid means, which is an instruction not to charge on that reading. Goodman IOG-4048C and the ICP grid (428 01 5106 00) supply the dashed regions themselves. Trane 88-M5MHWUN-1A-EN is the ductless installer guide behind the mini-split fork: it publishes no superheat or subcooling procedure at all, which is why this tool declines to issue a reading-based charge verdict on ductless equipment, and we state that as evidence about THAT guide rather than about every ductless machine. Rheem RD16AY supplies the evaporator-icing instruction the engine will not charge through. Where these documents route the technician to a weigh-in or to the unit’s own charging procedure, this tool routes there too instead of grading a reading the manufacturer does not charge from.
The per-machine charge-target corpus (registered manufacturer books, cited by form number): Where a specific machine's target subcooling is written, quoted from that manufacturer's own book with its form number. 15 documents across 7 brand families are registered and content-pinned: Carrier (SM10-R454B); Goodman (IOD-4064A, IOG-4048C, IOG-4064A); York (5391577-UIM-B-0718, 6411591-UIM-B-0824, 6694740-UIM-B-1025); Lennox (100108); Nortek (708921E, 7094080); Rheem (92-104921-25-04, 92-110354-01-01); Trane (11-AC22D1-1, 18-AC94D1-4-EN, 4TWX6060E-SF-1A). The tool publishes NO target subcooling value of its own from any of them. What it publishes is WHERE the figure lives on that machine, what that manufacturer calls it, the verbatim sentence it is read from, and which model series that sentence covers - so a claim read out of one book stops at the machines that book's own cover names. Where a book's current revision cannot be established, or where its own pages disagree, the value stays withheld and the reason is printed instead.
York ST-022-12, Figures 1 and 2 (example charging charts): The dose and the wait in the protocol loop: add or remove charge in one-ounce increments and let the system stabilize for ten minutes, repeating until the reading is in band. York prints these as examples and says so, and the tool passes that scope through rather than presenting the increment as a universal specification.
Rheem RD16AY / RD18AY section 5.7, and Lennox 13ACX 506374-01 page 20: The two hazards this engine will not charge through. Rheem's instruction covers running a system at a suction pressure that will ice the evaporator coil, and it is quoted with its own scope, which names cooling mode. Lennox states the low-superheat floor below which refrigerant must not be added, because liquid reaching the compressor is damage happening in that instant rather than a charge level. Both are carried on every branch, including the branches where a charging instruction is being withheld.
Copeland discharge-temperature guidance, and Proctor Engineering on airflow and capacity: The two checks that sit beside the charge rather than inside it. Copeland's discharge-line temperature limit is what the tool watches for a compressor running hot. Proctor's finding that a passing temperature split can also mean low airflow AND low capacity together is why a passing split is not treated as proof the air side is healthy.
Honeywell, March 2016 version 8: Retrofit Guidelines R-404A/R-507A to R-448A Solstice N40. Names, of the fluids this site carries, R-404A and R-448A. The sentences this site holds from it are at page 1 (taken from the file's own text rather than the rendered page), page 3 (taken from the file's own text rather than the rendered page) and page 4 (taken from the file's own text rather than the rendered page). Fetched 2026-09-05 from prod-edam.solstice.com. https://prod-edam.solstice.com/content/dam/honeywell-edam/pmt/oneam/en-us/refrigerants/documents/pmt-am-solstice-n40-refrigeration-retrofit-tech-guide.pdf
Honeywell, 3455 FP I (August 2019): HCFC/HFC to HFO Blend Retrofit Guidelines, Commercial Refrigeration (R-22/R-402A/R-404A/R-408A/R-507A to R-448A). Names, of the fluids this site carries, R-22, R-404A and R-448A. The sentences this site holds from it are at page 10 (read by rendering the page), page 21 (read by rendering the page) and page 22 (taken from the file's own text rather than the rendered page). Fetched 2026-09-05 from prod-edam.honeywell.com. https://prod-edam.honeywell.com/content/dam/honeywell-edam/pmt/oneam/en-us/refrigerants/documents/Retrofit-guide-Solstice-N40-R448A-from-22-402-408-507-404.pdf
Copeland, 2021ET-31 (7/21): Refrigerant changeover guidelines HFC R-404A to R-407H/R-448A/R-449A/R-452A. July 2021. Names, of the fluids this site carries, R-404A, R-448A and R-449A. The sentences this site holds from it are at page 1 (read by rendering the page) and page 2 (taken from the file's own text rather than the rendered page). Fetched 2026-09-05 from webapps.copeland.com. https://webapps.copeland.com/online-product-information/Publication/LaunchPDF?Index=AEB&PDF=2021ECT-31
Copeland, 95-14 R11 (7/21): Refrigerant changeover guidelines HCFC R-22 to HFC R-407A/C/F/H, R-448A, R-449A or R-427A. Revision 11, July 2021. Names, of the fluids this site carries, R-22, R-407A, R-407C, R-448A and R-449A. The sentences this site holds from it are at page 1 (read by rendering the page) and page 2 (taken from the file's own text rather than the rendered page). Fetched 2026-09-05 from webapps.copeland.com. https://webapps.copeland.com/online-product-information/Publication/LaunchPDF?Index=AEB&PDF=95-14
Copeland, AE22-1182 R26: Liquid Refrigerant Control in Refrigeration and Air Conditioning Systems. June 2024. Its superheat statements name no particular refrigerant, so it is cited wherever a commercial fluid is read. "A well designed, durable, and efficient compressor for refrigeration, air conditioning, or heat pump duty is primarily a vapor pump designed to handle a small quantity of liquid refrigerant and oil." The sentences this site holds from it are at pages 9 to 10 (read by rendering the page). Fetched 2026-09-05 from webapps.copeland.com. https://webapps.copeland.com/online-product-information/Publication/LaunchPDF?Index=AEB&PDF=1182
Copeland, AE-105 R3 (5/18): Refrigeration Manual Part 5, Installation and Service. Revision 3, May 2018. Its superheat statements name no particular refrigerant, so it is cited wherever a commercial fluid is read. Its measuring sentence sits under "5. Charging By Superheat", which opens: "On small unitary systems equipped with capillary tubes, the operating superheat may be used to determine the proper charge." Its receiver-charging statements are general. The sentences this site holds from it are at page 74 (taken from the file's own text rather than the rendered page) and page 75 (taken from the file's own text rather than the rendered page). Fetched 2026-09-05 from media.copeland.com. https://media.copeland.com/ff6556eb-dbad-4757-8ef4-b16d00377e59/AE105-Installation%20and%20Service.pdf
Heatcraft Refrigeration Products, H-IM-CU-0725 Version 010, Part No. 25014601: Installation and Operations Manual, Condensing Units. July 2025. Names, of the fluids this site carries, R-404A, R-407A, R-407C, R-448A and R-449A. The sentences this site holds from it are at page 7 (taken from the file's own text rather than the rendered page), page 24 (taken from the file's own text rather than the rendered page) and page 30 (read by rendering the page). Fetched 2026-09-05 from assets.heatcraftrpd.com. https://assets.heatcraftrpd.com/literature/installation-and-operation-manual/condensing-units-and-packaged-systems/current/H-IM-CU.pdf
Heatcraft Refrigeration Products, H-IM-UC-0626 Version 04, Part No. 25008201: Installation and Operations Manual, Unit Coolers. June 2026. Names, of the fluids this site carries, R-404A, R-407A, R-407C, R-448A and R-449A. The sentences this site holds from it are at page 6 (read by rendering the page). Fetched 2026-09-05 from www.heatcraftrpd.com. https://www.heatcraftrpd.com/dA/372b2b9e1e/H-IM-UC-HFC.pdf

The table values are looked up and interpolated from the datasheet within its disclosed tolerance, not measured here. The rack statements are quoted, not computed: a publisher's own conditions print on the adjacent line, and a document revised after the fetch date shown is not reflected until it is fetched again. The equipment's own literature has final say over any figure on this page.

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The calculatorRun your own numbersThe number above is the general case. Open the Superheat & Subcooling Calculator and put your own figures in.Your AIAsk it in plain EnglishConnect Intry to your AI once (ChatGPT, Claude, Cursor), then just ask. It runs the numbers and hands back the verdict and the source.The appKeep the whole jobSave your readings into one job in the free app, ready for the next step.